Screened spark plug



Jan. l, 1957 R P, CUNY ET AL 2,7?6g4 SCREENED SPARK PLUG.

Filed Feb. 26, 1955 IN V EN TORS R/CHAD F? CUNY RUB/ERT W/ED/ HfORA/EyUnited States Patent SCREENED SPARK PLUG Richard P. Curry, Union City,and Robert Wiedis, May- Wood, N. J., assignors to Bendix AviationCorporation, Teterboro, N. J., a corporation of Delaware ApplicationFebruary 26, 1953, Serial No. 339,138

1 Claim. (Cl. 317-96) The present invention relates to spark plugs andmore particularly to spark plugs for use in a highly turbulentatmosphere.

In combustion chambers such as in a fuel air starter where ignition of afuel and air mixture is required in a highly turbulent atmosphere,ignition is extremely diicult. The high turbulence of the swirling airin a combustion chamber has a tendency to diffuse the spark energybefore ignition can take place.

In the present invention a perforated cylindrical screen is placedaround the electrode portion of a high tension spark plug. This permitsignition to take place in a highly turbulent atmosphere as the screenacts to lower the velocity of and to disperse the charge in theneighborhood of the spark.

It is an object of the present invention to provide novel shieldingmeans for spark plugs.

Another object of the invention is to provide an improved spark plug foruse in a highly turbulent atmosphere.

Another object of the invention is to provide improved ignition meansfor igniting a mixture of fuel and air in a highly turbulent atmosphere.

The above and other objects and features of the invention will appearmore fully hereinafter from a consideration of the following descriptiontaken in connection with the accompanying drawing wherein oneernbodiment of the invention is illustrated by way of example.

In the drawing, the single figure is a partial cutaway view of a fuelair starter embodying the invention.

Referring to the drawing, a starter is indicated generally by thenumeral 1 and has a housing 2 adapted to house the turbine and geartrain (not IShown) of the starter. A combustion chamber 3 is secured tothe housing 2 by bolts 4 or in any other conventional manner. Thecombustion chamber 3 has an opening 4 adapted to receive a bushing 5which may be secured to the wall of the combustion chamber by welding orin any other conventional manner. The bushing 5 has a shoulder 2,776,394Patented Jan. 1, 1957 "ice 6 adapted to receive a screen 7. The screen 7is perforated with a plurality of openings 8. A bushing 9 is adapted toscrew into the bushing 5 and serves to hold the screen 7 against theshoulder 6. A pin 10 prevents the bushing 9 from turning.

The bushing 9 is adapted to receive spark plug 11 having electrodes 12and 13. An electrical conductor 1.4i is adapted to connect the sparkplug 11 in a conventional manner to a source of electrical energy (notshown).

The combustion chamber 3 has an inlet 15 through which a mixture of fueland air under pressure enter the chamber 3.

In operation, a mixture of fuel and air under pressure enters thecombustion chamber 3 through the entrance 15 and is ignited by means `ofthe spark plug 11. The perforated screen 7 surrounding the electrodes 12and 13 lower the velocity or the mixture of fuel and air and therebypermit ignition to take place. In other words the turbulency in thevicinity of the electrodes is reduced and excessive diffusion of thespark energy is prevented.

Although only one embodiment of the invention has been illustrated anddescribed, various changes in the form and relative arrangement of theparts, which will now appear to those skilled in the art may be madewithout departing from the scope of the invention.

What is claimed is:

Ignition means for use in a combustion chamber having a highly turbulentatmosphere and a wall defining said chamber, comprising a rstinteriorly-threaded bushing adapted to be secured to and in the wall ofsaid combustion chamber and being further adapted when so secured toextend an appreciable distance into said combustion chamber, a secondinteriorly and exteriorly threaded bushing screw-threadedly engaged insaid rst bushing, said first bushing having an inwardly projectingshoulder, a tubular wire screen having a radially outwardly extendingannular end portion engaging the inner wall -of Isaid shoulder, saidscreen having said annular end portion thereof clamped between saidinner wall of said shoulder of said irst bushing and the inner end ofsaid second bushing, said screen having another portion adapted toextend into said combustion chamber an appreciable distance inwardly ofthe inner end of said first bushing, and a spark plug screw-threadedlyengaged in -said second bushing, and said spark plug having fingerelectrodes extending into said tubular wire screen from said plug.

References Cited in the le of this patent UNITED STATES PATENTS

